diff --git a/railties/lib/rails/vendor_gem_source_index.rb b/railties/lib/rails/vendor_gem_source_index.rb
index dc821693acb18..5b7721f303f84 100644
--- a/railties/lib/rails/vendor_gem_source_index.rb
+++ b/railties/lib/rails/vendor_gem_source_index.rb
@@ -81,7 +81,7 @@ def refresh!
             spec.files = files
           else
             $stderr.puts("config.gem: Unpacked gem #{dir_name} in vendor/gems not in a versioned directory."+
-                         " Giving up.") unless @silence_spec_warnings
+                         " Giving up.") unless @@silence_spec_warnings
             next
           end
         end
@@ -137,4 +137,4 @@ def size
     end
 
   end
-end
\ No newline at end of file
+end